The present invention relates to a magnetic card reader with a movable magnetic head for recording data on and reading data out of a magnetic card.
In magnetic card readers with movable magnetic heads, the inserted magnetic card is conveyed on a carrier to a specified position, where it is stopped. The magnetic head is moved back and forth, in sliding contact with the magnetic stripe of the stopped magnetic card, thereby recording or reading-out information.
To avoid a false card other than the magnetic card being inserted, a card-intercept member like a shutter is installed in the path of the magnetic card. A prehead is installed around the entrance to the magnetic card path to examine the inserted magnetic card. Thus, two magnetic heads are needed: a main magnetic head for recording and reading out information, and a prehead for opening and closing a shutter and the like.
A magnetic card conveyed on the carrier is identified by a detection means such as a photo sensor and is stopped at a specific position. Thereby an error occurs within several millimeters from the specified stop position in the longitudinal direction of magnetic card. Ordinarily, the magnetic stripe of the magnetic card includes an area at a specific distance from the end of the magnetic stripe, where data area control is provided, that is, where no recording of data is done. Therefore, if variations happen in the magnetic card stopping position, it will be impossible to make uniform control of the magnetic head record or read-out starting position in accordance with the data area control value.
When in action, the magnetic head has to move precisely in sliding contact with the specified magnetic stripe. For this reason, the so-called "positioning" of the magnetic head is an essential requirement; if this positioning accuracy is low, it will be impossible either to make a reliable reading out of information from the magnetic stripe; or to record information at specified spots on the magnetic strip.
Another essential requirement for precise recording and reading out of information is that, when in action, the magnetic head must be pressed to the magnetic stripe of the magnetic card in perfectly perpendicular relationship.
Moreover, the magnetic head is interlocked with a motor for recording and reading out of information; therefore unless the motor keeps its specified r.p.m., the moving speed of the magnetic head will vary. Thus for the purpose of reliable recording and reading out of information, the r.p.m. of the motor has to be controlled so that a specific speed of the magnetic head can be maintained.